Seth Rosen
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Seth Rosen Email & Phone Number

CEO of CustomMade | Boston-Based Venture Partner for WTI | Serial E-commerce & Internet Entrepreneur at Western Technology Investment
Location: Greater Boston, United States 8 work roles 3 schools
1 work email found @m-g.com 7 phones found area 617 LinkedIn matched
✓ Verified August 2026 4 data sources Profile completeness 100%

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Work email s****@m-g.com
Direct phone (617) ***-****
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Role
CEO of CustomMade | Boston-Based Venture Partner for WTI | Serial E-commerce & Internet Entrepreneur
Location
Greater Boston, United States

Who is Seth Rosen? Overview

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Seth Rosen is listed as CEO of CustomMade | Boston-Based Venture Partner for WTI | Serial E-commerce & Internet Entrepreneur at Western Technology Investment, based in Greater Boston, United States. AeroLeads shows a work email signal at m-g.com, phone signal with area code 617, and a matched LinkedIn profile for Seth Rosen.

Seth Rosen previously worked as Venture Partner at Western Technology Investment and Founder & CEO at Custommade. Seth Rosen holds Bachelor'S Degree, Psychology, English Literature from Boston University.

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Email format at Western Technology Investment

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srosen@m-g.com
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Profile bio

About Seth Rosen

I have always been interested in old-line industries ripe for disruption. This interest has led me to acquire several website properties and businesses and scale them to become global sector leaders including:► Acquiring CustomMade.com in 2009, raising more than $30M backed by top-tier VCs, and turning it into an e-commerce marketplace connecting consumers with makers of custom products ► Repurchasing and relaunching CustomMade.com in 2015 and growing it to become the world's largest online custom jeweler► Acquiring and turning around the web properties International Gem Society and Ganoksin. These websites are now the largest in their respective niches (gems and jewelry manufacture), and attract 30M website visitors annuallyMy early career included commercial real estate investment banking with Meredith & Grew as a member of their debt and equity capital markets group, where I became one of the youngest partners in the firm's 120-year history at age 26. In 2021, I joined the Palo Alto-based investment firm Western Technology Investment (WTI) as a venture partner focused on the Boston market. As CEO of one of their current portfolio companies and a two-time customer of the firm, I offer a unique perspective to founders of venture-backed businesses considering venture debt.I’ve lived in Boston since 1999 and received my undergraduate degree from Boston University before completing my MBA and MST (Master of Science, Taxation) at Bentley University. Outside of work, I collect 19th- and 20th-century American art, and am a hobby gemologist and a former cycling instructor. Areas of expertise include: Venture Capital, Venture Debt, & Investments | Start-up Fundraising | E-commerce | Custom Jewelry | Gems & Gemology | Entrepreneurship | Business Turnarounds | Structured Credit

Listed skills include Entrepreneurship, Strategy, Venture Capital, Financial Modeling, and 42 others.

Current workplace

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Western Technology Investment
Western Technology Investment
CEO of CustomMade | Boston-Based Venture Partner for WTI | Serial E-commerce & Internet Entrepreneur
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8 roles · 26 years

Seth Rosen work experience

A career timeline built from the work history available for this profile.

Venture Partner

Current

Portola Valley, Ca, Us

After initially connecting with WTI as the CEO of one of their portfolio companies, I had the opportunity to join this private investment firm as a venture partner representing the Boston market. Founded in 1980, WTI pioneered the concept of venture debt to fill a capital need in the market. We understand and embrace the inherent risks associated with lending to early- and mid-stage technology businesses. Four decades later, our goal remains unchanged - to help visionary entrepreneurs transform their businesses, realize their full potential, and hopefully change the world. We've invested over $6B in companies such as Google and Facebook, as well as over 1,300 more at all phases of growth. Our approach is a good fit for businesses that either:► Have already raised VC funding and would like more runway to achieve milestones or drive growth► Are currently raising VC and would like to minimize dilution by raising both debt and equity simultaneously, which I've personally done with WTI

Jan 2021 - Present

Founder & Ceo

Current

Cambridge, Massachusetts, Us

In 2015, I purchased back the assets of the business in partnership with WTI, and relaunched the site to become the world's largest online custom jeweler. Because CustomMade already had tens of thousands of customers, we took over managing the jewelry design and manufacturing, and built an entire software system and business infrastructure for a fully online direct-to-consumer business. Today, we custom design thousands of pieces for over 50K customers per year and we're still growing rapidly.

2015 - Present ~11 yrs 7 mos

Co-Founder, President & Board Chairman

Cambridge, Massachusetts, Us

I co-founded CustomMade Ventures Corp. to buy CustomMade.com with my longtime friend and business partner, Mike Salguero. At the time, the website was a subscription-model business selling marketing services for a membership fee, but we transitioned it into an e-commerce business that facilitated transactions between makers/artisans and consumers who wanted custom-designed furniture, jewelry, housewares, etc. The marketplace attracted over 10M visitors annually and over 21K makers across the US and Canada. We raised more than $30M and were backed by top-tier VCs, including a lead investment from Google Ventures (the venture capital arm of Google, Inc.), as well as Atlas Venture, First Round Capital, and Schooner Capital.The business was featured in media outlets such as The Wall Street Journal, The New York Times, The Boston Globe, The Boston Business Journal, Forbes Magazine, Maxim Magazine, Bloomberg, CNN Money, Fox News, Fox Business, Shape Magazine, Wired Magazine, The Huffington Post, Fast Company, Entrepreneur Magazine, and others.In 2015, CustomMade Ventures entered into a definitive agreement with Wayfair (NYSE: W) to hire CustomMade’s employee base, after which the company's assets were sold.

Apr 2009 - Apr 2015

Owner

Current

As a gemstone collector who wanted to learn more about gemology, I'd been a member of the International Gem Society since 2007. When the IGS owner announced his retirement in 2012, I knew it was the perfect opportunity to both steward the property as a collector and grow it as an entrepreneur. Since the acquisition, my wife Lisa and I have scaled the site from attracting just 180K annual visitors to over 25M today. We also grew membership from a few hundred members to 15K members and became the world's largest gemology site.

2012 - Present ~14 yrs 7 mos

Owner

Current

Pathumtani, Th

Adding to our International Gem Society portfolio, my wife and I acquired Ganoksin.com, a technical resource website for jewelers originally launched in 1995. Since acquiring it in 2016, we have grown the site 7x to become the world's largest resource for professional jewelry makers, attracting over 3M visitors per year and a membership network of 25K worldwide. Ganoksin is also home to "The Orchid Forums," the largest, oldest, and most active online forum related to jewelry manufacturing and jewelry making. Ganoksin is a wholly-owned subsidiary of International Gem Society, LLC.

2016 - Present ~10 yrs 7 mos

Faculty Member – Cpe Program (Capital Markets Class)

Boston, Ma, Us

I taught the Capital Markets class in Boston University's CPE program. Broadly, I covered the structure and function of the entire debt and equity capital marketplace. Specifically, I covered topics related to asset-based lending including structured financial products, securitization, CMBS, RMBS, and CDOs in substantial depth. This experience taught me that; (a) I love to teach, and (b) teaching is not a passive endeavor. Despite being asked to take over the class permanently in the coming years, I decided this was something better pursued later in life.

2008 - 2009 ~1 yr

Vice President & Shareholder

Toronto, Ontario, Ca

After working in real estate full time while in college, I joined the major New England commercial real estate investment firm Meredith & Grew as a member of their debt and equity capital markets group. During this time, I focused on structured real estate finance and securitized lending, and placed over $750M in transactions. I became a shareholder at age 26 - one of the two youngest partners in the 120-year history of the firm. Meredith & Grew sold to First Service Corporation (NASDAQ: FSV) in 2008. I was deeply privileged to be part of the firm during its final years as a private partnership. I left the firm shortly after the sale was consummated.

2004 - 2009 ~5 yrs
3 education records

Seth Rosen education

Bachelor'S Degree, Psychology, English Literature

Boston University

Master Of Science In Taxation - Mst

Bentley University

Master Of Business Administration - Mba, Concentration In Taxation & Structured Finance

Bentley University
FAQ

Frequently asked questions about Seth Rosen

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What company does Seth Rosen work for?

Seth Rosen works for Western Technology Investment.

What is Seth Rosen's role at Western Technology Investment?

Seth Rosen is listed as CEO of CustomMade | Boston-Based Venture Partner for WTI | Serial E-commerce & Internet Entrepreneur at Western Technology Investment.

What is Seth Rosen's email address?

AeroLeads has found 1 work email signal at @m-g.com for Seth Rosen at Western Technology Investment.

What is Seth Rosen's phone number?

AeroLeads has found 7 phone signal(s) with area code 617 for Seth Rosen at Western Technology Investment.

Where is Seth Rosen based?

Seth Rosen is based in Greater Boston, United States while working with Western Technology Investment.

What companies has Seth Rosen worked for?

Seth Rosen has worked for Western Technology Investment, Custommade, International Gem Society, The Ganoksin Project, and Boston University.

How can I contact Seth Rosen?

You can use AeroLeads to view verified contact signals for Seth Rosen at Western Technology Investment, including work email, phone, and LinkedIn data when available.

What schools did Seth Rosen attend?

Seth Rosen holds Bachelor'S Degree, Psychology, English Literature from Boston University.

What skills is Seth Rosen known for?

Seth Rosen is listed with skills including Entrepreneurship, Strategy, Venture Capital, Financial Modeling, Financial Analysis, Leadership, Management, and Start Ups.

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